Field
The present disclosure generally relates to circuits and method for reducing or eliminating reference spurs in fractional-N frequency synthesis in radio-frequency (RF) applications.
Description of the Related Art
A radio-frequency (RF) communication system typically relies on one or more operating frequencies. A clean and stable signal having a desired operating frequency is highly desirable.
In many RF systems, a frequency synthesizer can provide a signal with an operating frequency through use of a phase-locked loop (PLL). In many operating situations, a PLL can suffer from undesirable effects such as phase noise or spurious tones (spurs). Phase noise typically refers to small variations from the intended operating frequency. Spurs are typically large unwanted frequency components that manifest themselves at some offset of the operating frequency.